Effects of dietary stevia extract supplementation on growth performance, serum biochemical indices, and intestinal health of yellow-feathered broilers.

Stevia, a perennial shrub from the genus Stevia in the Asteraceae family, contains active ingredients like chlorogenic acid and shows promise as a natural feed additive. Despite this potential, there is limited research on the impact of stevia extract specifically on yellow-feather broilers. The study aimed to evaluate the effects of dietary stevia extract with varying concentrations of chlorogenic acid on the growth performance, serum biochemical indices, and intestinal health of yellow-feathered broilers. A total of 425 1-d-old female yellow-feathered broilers were randomly allocated into five treatment groups with five replicates of 17 broilers each, and the feeding trial lasted 63 d. The groups included control and those supplemented with stevia extract at concentrations of 100, 200, 300, and 400 mg/kg. Results showed that adding 100 mg/kg of stevia extract to the basal diet significantly increased the daily weight gain (ADG) of the broilers while reducing the average daily feed intake and feed conversion ratio (F/G). However, supplementation with stevia extract at concentrations up to 300 mg/kg led to decreased final weight and ADG. Conversely, dietary supplementation with 100-200 mg/kg of stevia extract improved serum antioxidant capacity and reduced serum total cholesterol levels compared to the control group. Additionally, the cecum n-butyric acid level was significantly higher in the 200 mg/kg stevia extract group than in the control group. In conclusion, supplementing yellow-feathered broilers' diets with stevia extract can enhance growth performance, antioxidant and immune capacity, and intestinal health. The optimal concentration of stevia extract for these benefits is between 100 and 200 mg/kg.